Title : Productivity of crop rotation applying different tillage practices
Abstract:
Simple agronomic practises as crop rotation and soil tillage may lead to high yields of winter wheat (Triticum aestivum) and increase productivity of full crop rotation. The research described in this abstract was aimed to compare productivity of crop rotations depending on winter wheat proportion on it and soil tillage used. The field experiments were conducted in the Research and Study Farm “Peterlauki” (56° 30.658? N and 23° 41.580? E), in Latvia in four harvest seasons from 2016/2017 till 2019/2020, within the long-term experiment started in 2009. Three crop rotations which included the different proportions of winter wheat were studied (100% wheat (repeated winter wheat sowings), 67% wheat (three-year rotation with oilseed rape (Brassica napus spp. oleifera) and two years following wheat), 25% wheat (four-year rotation with faba bean (Vicia faba)–winter wheat–oilseed rape–spring barley (Hordeum vulgare)). Each rotation was grown in traditional (TT) and reduced (RT) soil tillage system. TT included mould-board ploughing at a depth till 22 cm, and soil cultivation after ploughing and before sowing, but RT – disc harrowing twice till a depth of 10 cm and cultivation before sowing. Split-plot design was used for arrangement of variants; each variant was four times replicated. Soil type at the site was Cambic Calcisol, clay. Productivity of crop rotation in this experiment was measured by energetic output (GJ ha-1) from production and economical evaluation (EUR ha-1). Yield of oilseed rape was calculated after sample sheaf analysis, but for other crops by direct combaining. Energy output was calculated from included crop’s above ground biomass energetic value (detected by ISO 18125:2017) and biomass yield. Economic evaluation was done as income and variable cost balance. The most energetically and economically valuable crops were wheat and oilseed rape. Significantly higher average yields of wheat were obtained in crop rotations "67% wheat" and "25% wheat" compared to repeated winter wheat sowings. Winter wheat yields after field beans and oilseed rape on average were higher using RT. Energy yields differences depending on the tillage systems were not significant. The significantly highest total energy yields were gained from rotations “67% wheat” and “25% wheat” with sequence of crops barley–faba bean–winter wheat–oilseed rape harvested in 2017–2020. Total average energy yield from all rotation “25% wheat” sequence varaints was reduced by low crop yields and energy output from spring crops (barley and faba bean) in dry 2018 and 2019, but the average energy yield obtained in this crop rotation was not mathematically significantly different from the result of rotation “100% wheat”. During experimental period, higher average economic benefit was obtained from crop rotations with diverse crops, mainly due to the positive fore-crop effect on winter wheat in rotations, compared to repeated sowing in long term. The highest economic profitability was achieved for a three-year crop rotation with 67% winter wheat and 33% winter oilseed rape using reduced tillage, followed by a four-crop rotation using both soil tillage systems. Both changing prices and changing crop yields affected the economic outcome over the years.
Audience Take Away Notes
- The research results proved sustainability of diversified rotations compared to continuous wheat on productivity
- It is possible to reduce tillage intensity to get competitive productivity from crop rotations.
- Productivity differences between crop rotations were strongly influenced by the meteorological conditions in the study period
